Polypropylene can be used in the manufacture of a variety of materials. In particular, polypropylene has been found useful in forming films and similar materials having a small or reduced thickness. One such material includes slit film tapes, which are used for a variety of applications. Common applications for polypropylene slit film tapes include carpet backing; industrial-type bags, sacks, or wraps; ropes or cordage; artificial grass and geotextiles. They can be particularly useful in woven materials or fabrics that require a high degree of durability and toughness. It is beneficial if the slit film tape can process easily and be resistant to breakage during all phases of the life of the tape, including manufacturing, weaving, and in the final fabric. Manufacturing of polypropylene slit film tapes is an extrusion process well known in the art, and inferior processability and strength can result in reduced extrusion efficiencies. Slit film tapes that break during weaving result in reduced loom efficiencies as well as a higher level of fabric defects.
Polypropylene slit film tapes are typically prepared from semi-crystalline, propylene homopolymers. These homopolymers are generally isotactic polymers prepared from stereospecific catalysts, such as Ziegler-Natta catalysts, which are well known in the art. While such polymers have provided polypropylene tapes with acceptable properties in the past, improvements in physical properties such as tenacity, toughness, elongation and reduced shrinkage are desirable.